AbstractAbstract
[en] The excitation energy per residue nucleon (E*/A) and fast and thermal light particle multiplicities are studied as a function of centrality defined as the number of grey tracks emitted Ngrey and by the mean number of primary hadron-nucleon scatterings (<ν>) and the mean impact parameter (< b>) extracted from it. The value of E*/A and the multiplicities show an increase with centrality for all systems, 14.6 GeV p-Au and 8.0 GeV π-Au and p-Au collisions, and the excitation energy per residue nucleon exhibits a uniform dependence on Ngrey
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(c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
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Journal Article
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Iverson, E. B.; Newby, R. J.; Hornback, D. E.; Smith, M. B. R.; Fields, N. E.; Efremenko, Y. V.; Kumpan, A.
American Nuclear Society - ANS, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)2014
American Nuclear Society - ANS, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)2014
AbstractAbstract
[en] The Spallation Neutron Source facility is a short-pulsed spallation source for condensed matter research using slow neutron scattering. Neutron beams with useful energies ranging from 0.1 meV to 10 eV are brought from a target-moderator-reflector assembly down neutron beamlines to scatter from a variety of materials under study. As of early 2014, SNS routinely provides 1.4 MW (time-averaged) proton power at around 940 MeV to a mercury spallation target at 60 Hz in sub-microsecond pulses. In nearly all cases, the pulsed nature of the neutron source is used, via time-of-flight techniques, to precisely identify the energy of each neutron detected. These neutrons are frequently of such low energy, and consequent slow velocity, that they are not detected until several additional accelerator pulses have taken place. A time-dependent background feature, commonly called the 'prompt pulse,' can contaminate the recorded data. This prompt pulse arises in part from fast and high-energy neutrons and photons produced during the various source reactions, and appears at the same apparent time as the proton pulse striking the target (that is, with negligible time-of-flight delay), often obscuring the data of interest in the individual experiment. We describe here measurements of the fast and high-energy neutron and photon background around the SNS neutron scattering instruments appearing in time with the SNS accelerator pulse structure. Our measurements to date indicate that the liquid scintillator array we have deployed can satisfactorily function in the SNS environment and provide neutron-photon discriminated time/energy spectra of background sources contribution to observed, problematic SNS scattering instrument backgrounds. We will continue measurements and analysis to provide unfolded neutron energy spectra, and through longitudinal studies correlate observed changes in those spectra to external changes at SNS. (authors)
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Sep 2014; 4 p; American Nuclear Society - ANS; La Grange Park, IL (United States); RPSD 2014: 18. Topical Meeting of the Radiation Protection and Shielding Division of ANS; Knoxville, TN (United States); 14-18 Sep 2014; ISBN 978-0-89448-714-9; ; Country of input: France; available on CD Rom from American Nuclear Society - ANS, 555 North Kensington Avenue, La Grange Park, IL 60526 (US)
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Book
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Conference
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ACCELERATOR NEUTRON SOURCE FACILITIES, BARYONS, BEAMS, CHALCOGENIDES, COHERENT SCATTERING, DIFFRACTION, ELEMENTARY PARTICLES, FERMIONS, HADRONS, NEUTRON SOURCE FACILITIES, NEUTRONS, NUCLEON BEAMS, NUCLEONS, PARTICLE BEAMS, PARTICLE SOURCES, PHOSPHORS, RADIATION SOURCES, SCATTERING, SPECTRA, SULFIDES, SULFUR COMPOUNDS, TIN COMPOUNDS
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